Facts about Mars

1. 15

   In 2008, NASA's Phoenix lander confirmed the presence of water ice just beneath Mars's surface near the north polar region by directly observing and analyzing frozen samples.

   MarsJun 6sharewaterexplorationpolar
2. 14

   Deimos, Mars's smallest moon, orbits so far from the planet that it takes 30 hours to complete one revolution, making it slower than Mars's 24.6-hour rotation.

   MarsMay 22shareastronomyorbitalmechanicsmeasurement
3. 13

   Gravitational pull on Mars is only 38 percent of Earth's, meaning a 100-pound person would weigh just 38 pounds on the Martian surface.

   MarsMay 21sharemeasurementphysicsgravity
4. 12

   Curiosity rover detected methane concentrations in Mars's atmosphere that fluctuate seasonally between 0.24 and 0.65 parts per billion, suggesting either geological or biological sources.

   MarsMay 21shareatmospherechemistryexploration
5. 11

   Sunset on Mars appears blue rather than red because fine dust particles scatter longer wavelengths of light, reversing Earth's typical orange sunset effect.

   MarsMay 21shareopticsatmospherevisual
6. 10

   A year on Mars lasts 687 Earth days, nearly twice as long as our own orbital period around the sun.

   MarsMay 21shareastronomymeasurementorbital
7. 09

   Below Mars's surface, subsurface water ice deposits contain more frozen water than all of Earth's polar ice sheets combined, according to radar data from orbital surveys.

   MarsMay 21sharewatergeologymeasurement
8. 08

   Iron oxide in Mars's rusty soil gives the planet its distinctive reddish color and comprises approximately 3 to 8 percent of the surface composition.

   MarsMay 21sharechemistrygeologycolor
9. 07

   Dust storms on Mars can grow so massive that they encircle the entire planet within weeks, as occurred in 1971 during Mariner 9's arrival.

   MarsMay 21shareweathermeasurementatmosphere
10. 06

    Mars's atmosphere is 95 percent carbon dioxide but only 1 percent as dense as Earth's, creating surface pressures equivalent to 30,000 feet above sea level.

    MarsMay 21shareatmospheremeasurementchemistry
11. 05

    Phobos, Mars's larger moon, orbits so close that it completes three revolutions around the planet every Martian day, making it appear to rise and set twice daily from the surface.

    MarsMay 21shareastronomymeasurementmotion
12. 04

    At minus 143 degrees Celsius, Mars's average surface temperature is cold enough to freeze carbon dioxide directly into dry ice, which forms seasonal polar caps.

    MarsMay 21shareclimatemeasurementchemistry
13. 03

    Valles Marineris, a canyon system stretching 4,000 kilometers across Mars, reaches depths of 7 kilometers in places, dwarfing Earth's Grand Canyon.

    MarsMay 21sharegeologymeasurementtopography
14. 02

    One Martian day, called a sol, lasts 24 hours and 39 minutes, making it remarkably similar to Earth's 24-hour rotation period.

    MarsMay 21shareastronomymeasurementplanetary
15. 01

    The largest volcano in the solar system, Olympus Mons on Mars, reaches 21.9 kilometers high and spans 600 kilometers in diameter.

    MarsMay 21sharemeasurementgeologycomparison